Certain 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides are inhibitors of β-lactamase and, when used in conjunction with β-lactam antibiotics, can be effective for the treatment of bacterial infections. See, for example, U.S. Pat. No. 8,487,093 which discloses 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and their synthesis from a ketosulfoxonium ylide intermediate containing an amide side chain, where the ylide intermediate is cyclized to a 5-oxo-piperidine-2-carboxamide using an Ir, Rh, or Ru catalyst. Similarly, Baldwin et al. disclose the transformation of lactone-derived β-ketosulfoxonium ylides into β-oxonitrogen heterocycles in the presence of a rhodium catalyst. See Baldwin et al., 1993, J. Chem. Soc., Chem. Commun. 18:1434-1435. Mangion et al. disclose iridium-catalyzed X-H insertions (e.g., N—H insertions) of sulfoxonium ylides. See Mangion et al., 2009, Org. Lett., 11:3566-3569 and Mangion et al., 2011, Org. Lett. 13:5480-5483.
U.S. Pat. No. 7,112,592 discloses heterocyclic compounds and their salts, processes for making the compounds and methods of using the compounds as antibacterial agents. One such compound is sodium salt of 7-oxo-6-(sulphoxy)-1,6-diazabicyclo[3.2.1]octane-2-carboxamide. U.S. Patent Application Publication No. US2003/0199541 discloses methods for preparing azabicyclic compounds which are useful as medicaments, in particular anti-bacterial agents. International Patent Application Publication Nos. WO 2002/10172, WO2008/039420 and WO2012/172368 disclose methods for preparing certain 7-oxo-1,6-diazabicyclo[3.2.0]heptane-2-carboxamides or trans-7-oxo-6-(sulphoxy)-1,6-diazabicyclo[3.2.1]octane-2-carboxamides which are useful as β-lactamase inhibitors.
International Patent Application Publication No. WO2010/126820 discloses the preparation of alkyl esters of N-protected oxo-azacycloalkylcarboxylic acids. These esters can be used as intermediates in the synthesis of 7-oxo-1,6-diazabicyclo[3.2.1]octane-2-carboxamides and esters.